This invention relates to an improved method for loading cargo, for example, into the hold of a vessel, and the apparatus for carrying out this improved method.
Over the past several decades the major portion of loose bagged or packaged cargo has been loaded and discharged from vessels, and stored in terminals, using skids or pallets. For stevedoring operations, that is the operation of loading or unloading cargo onto or from ships using hoisting apparatus, pallets are used that vary in size from 4'.times.6' to 5'.times.7' depending on the nature of operations. Such pallets are generally constructed of 1" hardwood boards with three intermediate 4".times.4" stringers between the reversible working surfaces. Channels on each end provide lifting slots for gear to be inserted for hoisting.
Warehousing facilities, on the other hand, generally use pallets that differ in size and construction from stevedoring pallets, since fork lifts, rather than hoists, are used to transport the former. Warehouse pallets are typically about 40".times.48" and have intermediate stringers flush with the sides in the length of the pallet. The stringers are generally equipped with slots to allow forklift trucks entry from both the width and length of the pallet.
As an example of a loading operation, the bagged or packaged cargo is received prepalletized at the terminal on, for example, open flatbed trucks or closed trailers, and must be stacked by lifttruck on the warehouse pallets for storage in the terminal. In the terminal, two warehouse pallets are often stored on a single 4'.times.6' stevedoring pallet to lend tiering stability.
The stevedoring pallet, supporting the two warehouse pallets, is thereafter brought along side the ship. A hoist is connected to the stevedoring pallet, and the three pallets, supporting the cargo, are hoisted on board the vessel. On board, the cargo is removed from the pallets and stacked for storage on the vessel by hand. The two warehouse pallets and the stevedoring pallet are then returned to the dock.
For a vessel loaded, for example, with 12,000 metric tons of bagged sugar, at 1.2 metric tons per warehouse pallet, 10,000 warehouse pallets and 5,000 stevedore pallets would be hoisted into the vessel during loading, emptied by hand, and transported off the vessel. Accordingly, the aggregate number of pallet handlings for this 12,000 metric ton load would be 30,000 pallet moves.
Alternatively, the bagged or packaged cargo may be received by rail, truck, or a vessel and handled onto stevedoring pallets for storage in the terminal to await shipment. In that case, the stevedoring pallets and the cargo thereon are hoisted on board the vessel and the empty pallets returned to the dock.